23.8.9.1 C API Prepared Statement Type Codes

The buffer_type member of
MYSQL_BIND structures indicates the data type
of the C language variable bound to a statement parameter or
result set column. For input, buffer_type
indicates the type of the variable containing the value to be
sent to the server. For output, it indicates the type of the
variable into which a value received from the server should be
stored.

The following table shows the permissible values for the
buffer_type member of
MYSQL_BIND structures for input values sent
to the server. The table shows the C variable types that you can
use, the corresponding type codes, and the SQL data types for
which the supplied value can be used without conversion. Choose
the buffer_type value according to the data
type of the C language variable that you are binding. For the
integer types, you should also set the
is_unsigned member to indicate whether the
variable is signed or unsigned.

For input string data, use MYSQL_TYPE_STRING
or MYSQL_TYPE_BLOB depending on whether the
value is a character (nonbinary) or binary string:

MYSQL_TYPE_STRING indicates character
input string data. The value is assumed to be in the
character set indicated by the
character_set_client system
variable. If the server stores the value into a column with
a different character set, it converts the value to that
character set.

MYSQL_TYPE_BLOB indicates binary input
string data. The value is treated as having the
binary character set. That is, it is
treated as a byte string and no conversion occurs.

The following table shows the permissible values for the
buffer_type member of
MYSQL_BIND structures for output values
received from the server. The table shows the SQL types of
received values, the corresponding type codes that such values
have in result set metadata, and the recommended C language data
types to bind to the MYSQL_BIND structure to
receive the SQL values without conversion. Choose the
buffer_type value according to the data type
of the C language variable that you are binding. For the integer
types, you should also set the is_unsigned
member to indicate whether the variable is signed or unsigned.